Telephone conferencing is an effective means of communication where multiple users may simultaneously participate in a call. An Internet Protocol Multimedia Subsystem (IMS) is an architectural framework for delivering Internet Protocol (IP) multimedia services. It was originally designed by the wireless standard 3rd Generation Partnership Project (3GPP), as a part of the vision for evolving mobile networks beyond the Global System for Mobile Communications (GSM). 3GPP systems comprise functionality for conferencing within the IMS based framework utilizing Session Initiation Protocol (SIP).